In a wireless communication technology, a power amplifier circuit is located at a front end of an emitter, and is used to implement signal amplification, so as to meet a power requirement for a transmitted signal. To meet a requirement on high power, as shown in FIG. 1, an existing power amplifier circuit is a balanced Doherty power amplifier circuit, which is equivalent to two Doherty amplifiers 1. In each Doherty amplifier 1, an input end of a peak amplifier P is connected to an input end of the power amplifier circuit by using a one-fourth wavelength line 2, and an input end of a mean amplifier M is connected to an input end of the power amplifier. That is, a same input signal is input to two peak amplifiers and two mean amplifiers. A working principle of the balanced Doherty power amplifier circuit lies in active-load pulling, where load impedance of the mean amplifier M and the peak amplifier P changes with different power of an input signal. Specifically, when input power is low and the peak amplifier P is not working, because of an impedance transformation function of the one-fourth wavelength line, a load corresponding to the mean amplifier M is 100 ohms; compared with a working condition with a load of 50 ohms, saturated output power of the mean amplifier M is reduced by 3 dB, and efficiency is relatively high in a case of low power output. When the input power increases, the peak amplifier P starts to work, and the load of the mean amplifier M changes from 100 ohms to 50 ohms; in a case in which an output peak voltage remains in a saturated state, the output power gradually increases and efficiency of the mean amplifier M is still high; the load of the peak amplifier P changes from infinity to 50 ohms. When the input power continues to increase until both the mean amplifier M and the peak amplifier P reach their peak power, both the load corresponding to the mean amplifier M and that corresponding to the peak amplifier P are 50 ohms. A matching unit in the figure is configured for load matching in a signal amplification process.
However, because working processes of the peak amplifier and the mean amplifier, as well as the devices themselves, are different, time delays, phases, or working statuses of two branches in each Doherty amplifier cannot precisely match; as a result, efficiency of the entire power amplifier circuit is reduced.